NWS Heat Advisories & Warnings Span 18 States, Affect 50 Million

A scorching heat wave that began in the High Plains is baking the Central Plains, and on Friday prompted warnings for the big cities of the Mid-Atlantic and Southeast. The combination of triple-digit heat and high humidity has prompted the National Weather Service (NWS) to issue heat warnings and advisories for at least 18 states from Kansas to New Jersey, south to Mississippi, putting at least 50 million people under some form of a heat alert. Heat watches and warnings are in effect for major metro areas such as St. Louis, Indianapolis, Columbus, Nashville, Charlotte, Raleigh, Richmond, Washington, D.C., Baltimore, Philadelphia, and New York.

The heat wave has already broken numerous longstanding records, which in some cases dated back to the Dust Bowl era of the 1930s. Many of the records being set have been for warm overnight low temperatures. In Des Moines, for example, the low temperature on Thursday was a tropical 81°F, breaking the old record for the date of 78°F that was set in 1931. According to the NWS, this was just the second time in the past 75 years when the low temperature was 81°F or warmer in this location.

When temperatures fail to cool below about 80 degrees at night, the risk of heat-related illness in persons without access to air conditioning, particularly the elderly, goes up dramatically, according to public health experts. The National Weather Service has been stressing heat safety tips, reminding Americans that heat is the top weather-related killer, with hundreds of deaths each year. Smoke from the wildfires in Colorado and other Western states is adding to concerns about poor air quality in the East, with numerous air quality advisories in effect on Friday.

During the June 22-to-28 period, there were 2,132 warm temperature records set or tied in the U.S., compared to 486 cold temperature records. This includes 267 monthly warm temperature records, and 54 all-time warm temperature records.

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http://www.climatecentral.org/news/rare-june-heat-wave-stifles-central-plains-east-coast/